FIG. 1 diagrammatically illustrates a mobile station (MS) 11 which accesses a server 13 via a cellular communications network 15 including an MSC/VLR 17 and an HLR 19. Various conventional components of the cellular network 15 (such as the base station system) are omitted for clarity of exposition. The cellular network may be a GSM (Global System for Mobility) network. An arrangement of this type is disclosed in WIPO document WO 96/20572, and in U.S. patent application Ser. No. 363,027 filed on Dec. 23, 1994, both of which documents are hereby incorporated herein by reference.
The server 13 is located externally relative to the cellular network 15, but is coupled to HLR for communication with the cellular network. The mobile station 11 sends a request for service to MSC/VLR 17, as indicated at 12 in FIG. 1. The request may be formatted according to the conventional Unstructured Supplementary Service Data (USSD) protocol. The USSD protocol is defined in the ETSI Draft prETS 300 625 (GSM 02.90 version 4.1.0), and in ETSI GSM 03.90 version 5.0.0, both of which documents are hereby incorporated herein by reference.
MSC/VLR 17 forwards the USSD request received from the mobile station 11 to HLR 19, which in turn forwards the request to the server 13. These communications are carried out using conventional MAP-USSD protocol, wherein MAP is the GSM acronym for Mobile Application Part. The server 13 can be any type of service node, and is typically capable of servicing a wide variety of mobile stations having a wide variety of operational characteristics. The server is capable of providing different levels of service commensurate with the different operational capabilities of the mobile stations. However, for a given request, the server has no way to determine what level of service is appropriate. Accordingly, the server 13 typically provides, in response to a USSD request for service, a generic level of service which is appropriate for the least sophisticated mobile station that can be expected to request service. The service is provided by the server in a USSD reply to the USSD request. The reply is passed from the server to HLR, from HLR to MSC/VLR, and from MSC/VLR to the mobile station.
Thus, mobile stations having higher levels of operational capability will typically receive a lower level of service that is commensurate with a mobile station having a lower level of operational capability. The higher level operational capabilities of the more sophisticated mobile stations are typically not utilized by the lower level of service that is provided by the server 13.
It is therefore desirable to enable a server to provide to each requesting mobile station a level of service commensurate with the operational capabilities of that mobile station.
In the present invention, the mobile station provides in its request for service information from which the server can determine the operational capabilities of the mobile station. Once the operational capabilities of the mobile station have been determined by the server, the server can then provide a level of service commensurate with those operational capabilities.